listEventInstances expands one recurring parent event into its individual
occurrences. Use the parent series ID, not an occurrence ID.
Example
Inputs
event is required. calendar defaults to primary. Optional maxResults
(1–2,500), pageToken, includeDeleted, RFC 3339 timeMin/timeMax, and IANA
timeZone constrain the page. account selects the Google account.
Output
Returns the same event page as List events. Each occurrence normally includesrecurringEventId and originalStart; use nextPageToken to continue.